fix: LLM 客户端自建大超时 Client，绕开 SDK 默认 60s unary 超时

CURSOR_MODEL=auto 时后端首 token 常超过 SDK 默认 unary_timeout，
自建带 DAILY_CURSOR_UNARY_TIMEOUT(300s)/DAILY_CURSOR_STREAM_TIMEOUT(900s)
的 Client 并显式传入 Agent.prompt，finally 中关闭释放资源。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

daily/llm_client.py

@@ -74,7 +74,7 @@ def _cursor_chat(system: str, user: str) -> str:
     api_key = (env("CURSOR_API_KEY") or "").strip()
     if not api_key:
         return ""
-    from cursor_sdk import Agent, AgentOptions, CursorAgentError, LocalAgentOptions
+    from cursor_sdk import Agent, AgentOptions, Client, CursorAgentError, LocalAgentOptions
 
     from daily.bridge_manager import warm_cursor_bridge
 
@@ -83,6 +83,17 @@ def _cursor_chat(system: str, user: str) -> str:
     warm_cursor_bridge()
     model = env("CURSOR_MODEL") or "composer-2.5"
     prompt = f"{system}\n\n{user}"
+
+    # SDK 默认 unary_timeout 只有 60s，CURSOR_MODEL=auto 时后端首 token 常超时；
+    # 自建带大超时的 Client 绕开 _default_client()，unary/stream 都放大。
+    unary_timeout = env_int("DAILY_CURSOR_UNARY_TIMEOUT", 300)
+    stream_timeout = env_int("DAILY_CURSOR_STREAM_TIMEOUT", 900)
+    client = Client(
+        base_url=os.environ["CURSOR_SDK_BRIDGE_URL"],
+        auth_token=os.environ["CURSOR_SDK_BRIDGE_TOKEN"],
+        unary_timeout=unary_timeout,
+        stream_timeout=stream_timeout,
+    )
     try:
         result = Agent.prompt(
             prompt,
@@ -91,9 +102,12 @@ def _cursor_chat(system: str, user: str) -> str:
                 model=model,
                 local=LocalAgentOptions(cwd=cwd),
             ),
+            client=client,
         )
     except CursorAgentError as exc:
         raise RuntimeError(f"LLM 调用失败：{exc.message}") from exc
+    finally:
+        client.close()
     if result.status == "error":
         raise RuntimeError(f"LLM 调用失败：{result.result or '未知错误'}")
     return (result.result or "").strip()